The invention relates to a charge-coupled device having a semiconductor body comprising a semiconductor layer of mainly the first conductivity type which adjoins a surface and in which a charge transport channel is defined for the storage and transport of information representing charge packets of the other type, this charge transport channel having at least two segments which can be connected in series with each other by means of a switchable connection, by means of which a charge packet that has been transported through the first segment of the charge transport channel may be transferred, as desired, to the second segment for further charge transport through the second segment.
Charge-coupled devices of the kind described here have an adjustable charge transport path and can be used for several applications. For example, several filters having different filter characteristics may be arranged beside each other on the semiconductor body, while the charge packets may be transported to the filter having the desired characteristic. Another application may be found in devices for multiplexing or demultiplexing signals. In other embodiments, it is possible to drain signals partly instead of transporting them to the second segment.
A charge-coupled device of the kind described above is known inter alia from Japanese Patent Application 51-103484 laid open to public inspection on 03-17-1978 under Kokai No. 53-29058. This Application describes a configuration in which the first segment, into which the charge is introduced, merges at a T crossing comprising a second a second and a third segment, whose charge transport directions are at right angles to the charge transport direction in the first segment. The switchable connections between the first segment on the one hand and the second and the third segment on the other hand are constituted by two insulated gates, by means of which the connection between the first segment on the one hand and the second or third segment on the other hand can be established and interrupted.
A disadvantage of such a coupling is that the freedom in designing the device is limited. For example, it is fairly difficult to provide in types of ccd's other than the meander type described in Kokai 53-29085 sharp bends in the charge transport channel without the electrical properties, such as the transport efficiency and the speed, being deteriorated. An even greater disadvantage is that, when the connection between the ccd segments to be coupled to each other extends over a larger distance, due to the use of one or more insulated gates as a switch, the transport time required to transport information form the first segment to the second segment becomes dependent upon the length of the connection.